Uncertainties and Systematic Effects on the estimate of stellar masses in high z galaxies

摘要

We discuss the uncertainties and the systematic effects that exist in the estimates ofthe stellar masses of high redshift galaxies, using broad band photometry, and how they affect thededuced galaxy stellar mass function. We use at this purpose the latest version of the GOODS-MUSIC catalog. In particular, we discuss the impact of different synthetic models, of the assumedinitial mass function and of the selection band. Using Charlot & Bruzual 2007 and Maraston 2005models we find masses lower than those obtained from Bruzual & Charlot 2003 models. In addition,we find a slight trend as a function of the mass itself comparing these two mass determinationswith that from Bruzual & Charlot 2003 models. As consequence, the derived galaxy stellar massfunctions show diverse shapes, and their slope depends on the assumed models. Despite thesedifferences, the overall results and scenario is observed in all these cases. The masses obtainedwith the assumption of the Chabrier initial mass function are in average 0.24 dex lower than thosefrom the Salpeter assumption, at all redshifts, causing a shift of galaxy stellar mass function of thesame amount. Finally, using a 4.5 pm-selected sample instead of a Ks-selected one, we add a newpopulation of highly absorbed, dusty galaxies at z = 2 - 3 of relatively low masses, yielding strongerconstraints on the slope of the galaxy stellar mass function at lower masses.